Materialism isn't a theory.
I'm not using the lexeme "popular" in the colloquial sense, but as a categorization. Popular literature is that which is non-technical (i.e., not intended for our colleagues). For example, literature in modern (quantum & relativistic quantum) physics assumes that one is familiar with vector spaces, functionals, etc., but not necessarily measure theory (at least not to the extent that mathematicians or those who deal with rigorous probability theory are). Technical literature in biblical studies or classics generally assumes knowledge not only of Latin and Ancient Greek but German and French or Italian.
You don't know my position.
All scientists rely on citations from other scientists. It's the foundation of all academic literature, the sciences included. Any technical paper, monograph, etc., will rely on a large number of quotations or simply citations from the literature.
Proof is for mathematics. We don't deal with proofs in science except in terms of mathematical proofs.
That's a theorem. Materialism is an axiom (or a set of axioms).
The Higgs was "discovered" in 2012, and the physics literature still reflects the fact that we don't actually know what we found because we lack both the language and the knowledge to connect "physics" with the "physical" (see the particle physics group's latest publications, the relevant APS papers, and the simplest source I know of: my blog:
The God Particle Discovered? Maybe Not).
You can't. Because apart from the various different solutions that result in different elementary particles, there's the ontological issues. There's a fairly non-technical volume
Ontological Aspects of Quantum Field Theory you might check out.
Conflicting results that at best are uninterpretable from a materialist perspective.
This is simply to say that the brain is a materialist cause of phenomena from the social sciences because it is assumed they are. It explains nothing and assumes everything relevant. Even grandmother neurons were vastly superior to such assertions.
None exist (currently).
I was a researcher and teacher at Harvard until my overly ambitious doctoral dissertation (demonstrating the inadequacy of any and all possible quantum theories of consciousness) required a change in graduate programs (basically, when you spend more time with mathematicians and physicists than those in your own lab, let alone your own department, you end up losing most of the possible support from your would-be "doctoral defense" committee, who don't appreciate your not producing or helping to produce research in the field and can't evaluate your work because they lack the requisite knowledge; so you go to MIT). However, my background is irrelevant. It's the literature that matters (actually, it's the truth that does but as access to it is mediated through things like scientific knowledge and familiarity with work in fields from philosophy to physics the literature is as good as we often get).